Self-aligning idler for conveyer belts



ec, 18, 1945. E. E. LA-NDAHL 2,391,249

SELF-ALIGNING ,IDLER FOR CONVEYER BELTS Filed Oct. "7. 1944 I5 3mm 0 m 151 MM Patented Dec. 18, 1945 v Eugene-.Ellandahl, Bennie-Mien. pnlicationflc'tober 7,1944,;SerialP10357509- (o1. iris-F202 This invention relates to idlers -of thetype adapted ,for usein .thesupport of conveyervbelts and is more particularlylconcerned with idlersof the';s elf-a1igning ,type which compensate automatically toproperly center the belt on the idler rolls :under operating conditions which tend'to cause the associated conveyer .belt to move laterallyto positionsout of proper registration with theidler rolls. g l t t 1 V llllhen the advancing run of an'elongated conveyer belt is improperly-loaded, that is, with the material being conveyed by the belt disposed 550 that it does not occupy .a balanced centralized positiononthe belt, there is a tendency for the belt .to move laterally of its supporting idler rolls. Eiforts have been made to overcome this tendencyby mounting the rolls on a supporting .frame which at its -center, is pivoted for swinging move ment about a substantially vertical axis carried by the stationary base structure of the idler assembly. However, with this construction, experience has disclosed that the pivoted roll-supporting frame possesses such inertia moments which following deflection thereof from its normal operating position, renders it diflicult to properly realign itself with other cooperating idlers and for this reason the same have not proved to be altogether satisfactory in practice.

Therefore, it is a primary object of the present invention to provide an improved conveyer beltsupporti-ng idler assembly having a center roll turnable about a fixed horizontal axis and a pair of side rolls turnable about axes disposed in acute angular relationship to the axis of the center roll and in diverging relation with respect thereto, and wherein provision is made for supporting the side rolls to admit of bodily turning movement thereof about vertical axes, whereby under conditions of improper belt loading-the side rolls automatically assume positions compensating for lateral misalignment of the belt and its subsequent restoration to positions properly centered on the idler construction.

It is another object of the invention to provide a self-aligning and antifriction idler assembly wherein the side rolls are supported for rotation on upwardly inclined spindles, the latter terminating at the inner end of each of the Side rolls in downwardly and vertically directed extensions which are rotatably received in vertically disposed bearings carried by the base frame of the assembly.

It is a further object of the invention to provide a belt idler assembly in which the lower ends of the vertically journaled extensions of the side roll spindles are provided withcranks whichjare pivotally united at theirouter ends with a link memberq so-that deflectionof one of the side xrolls from its normal operating position will causeicor responding and v compensating movement on the part of the other side roll. i

For a further understanding-of the invention, reference-isto be had to the following description and the accompanying drawing, wherein:

,Fig'. l is a top plan view of an idler .assembly for conveyer belts formed in accordance with-the present invention;

.Fig12 is a frontelevationalview thereof;

Fig. '3 is a vertical transverse sectional ,view

taken through the idler assemblyion the plane indicated bytheline '33 of Fig.2; v

Fig. 4 is a vertical longitudinal sectional View taken .throughoneof the end ,rollsshowing its pnortineispindle; g t

Fig. 5 is a similar view taken through the :middle roll. T

Referring more particularly to the drawing, the numeral I0 designates the base frame of my improved idler assembly. Mounted on the upper surface of the frame is a pair of spaced bearing brackets ll, these brackets being formed with bearings to receive the ends of 'a horizontally disposed shaft IZ on which isrotatably mounted a middle belt-supporting roll or pulley [3, antifriction thrust-receiving bearings [4 being disposed between the shaft l2 and the end walls 15 of said roll.

At each end of the middle roll, the assembly provides a pair of angularly disposed side rolls I6.

These rolls are rotatably supported on spindles ll, the longitudinal axes of the latter being upwardly inclined and acutely angular to the hori-,

zontally disposed longitudinal axis of the middle 7 roll, so that a conveyer belt 18 supported by and passing over the upper surfaces of said rolls will possess transversely a trough-like configuration for the support andretention of loose materials carried by the belt.

At the inner ends of the side rolls [6, the supporting spindles thereof terminate in downwardly directed substantially vertically disposed journaling extensions [9. These extensions are rotatably received in bearing openings 20 provided in the brackets I I, so that said extensions may turn about substantially vertical axes, turning with them the side rolls It. In order that turning movement of one of the side rolls will impart corresponding turningmovement to the other side roll, the lower ends of the extensions l9 terminate in diametrically reduced studs 2| which pass through openings provided in the base frame [0. The lower ends of these studs have fixed thereto crank arms 22, and the outer ends of these crank arms have pivoted'thereto as at 23 the ends of a connecting link 24.

By the use of an idler so constructed, it will be seen that when the belt tends to run toward one side of the assembly, a condition due to a number of causes, but most often produced by the'improper loading of material on narrow width belts particularly; theroll IE on the side toward which the belt tends to move will turn slightly from its normal operating position taking with it the opposite side roll with which it is connected and thereby causing the belt to be restored automatically to its normal centered position of operation. This arrangement is decidedly effective since the end or side rolls are of light construction and by being pivoted for turning movement about an arc of short radius, the same will read-. ily change positions in response to forces applied thereto by the conveyor belt. The middle roll or pulley, having. a stationary base, functions as a stabilizer, thus enabling the whole idler assemblyitojoperate efliciently in securing proper belt performance. Preferably; when viewed in plan, theaxes of the side or end roll I6 is slightly angular to the axis of the middle roll, as indicated by dotted lines in Fig. 1. By so disposing the axes of the rolls IB', their arrangement is rendered more'sensitive to operating conditions, causing the end rolls to rotate truly, somewhat after the manner of the mounting of the front wheels of automotive vehicles wherein a slight toe-in is provided.

'While Ihave, described what I consider tobe a preferred embodiment of my invention, nevertheless; it will be understood that the same is subject to certainvariation or modification withoutdeparture from the spirit and scope of the following claims;

I claim:

1. An idler assembly for the support of conveyer belts comprising a base, spaced bearing brackets carried by said base, a middle roll, means carried by said brackets supporting said middle roll for rotation about a substantially horizontal axis, an upwardly inclined side roll arranged at each end of said middle roll, spindles for the rotatable support of said side rolls, said spindles terminating at the inner ends of said side rolls in downwardly directed substantially vertically disposed extensions, the latter being turnably positioned in openings provided therefor in said brackets and disposed between the adjacent ends of the middle and side rolls,

g crank arms joined with the lower ends of said extensions, and a link member having its ends pivotally connected with the outer ends of said crank arms.

2. An idler assembly for the support of conveyer belts comprising a base, spaced bearing brackets carried by said base, a middle roll, means carried by said brackets supporting said middle roll for rotation about a substantially horizontal axis, an upwardly inclined side roll arranged at each end of said middle roll, spindles for the rotatable support of said side rolls, saidjspindlesterminating at the inner ends of said'side rolls in downwardly directed substantially vertically disposed extensions, the latter being turnably positioned in openings provided therefor in said brackets, said extensions occupying positions between the outer ends of the middle roll and the inner ends of the side rolls, crank arms joined with the lower ends of said extensions, and a link memb'er'having its ends pivotally connected with the outer' ends of said crank arms, the longitudinal axes of said side rolls when'the latter are viewed in plan being disposed in acute angular relationship to the EUGENE 'E. LANDAHL. 

